Field of the Invention
The present invention relates to an EGR control method of an internal combustion engine, and more particularly relates to an EGR control method of an internal combustion engine that performs EGR control respectively in two banks.
Background Art
As a prior art, there has been known a control device of an internal combustion engine including EGR mechanisms respectively in two banks as disclosed in Patent Literature 1 (Japanese Patent Laid-Open No. 2007-247612), for example. In the prior art, one-valve EGR control and both-valve EGR control are properly used by separately controlling EGR valves included by the respective banks. Thereby, in the prior art, a fresh air amount is increased while an EGR rate is compensated. Both-valve EGR control recirculates an EGR gas into an intake passage from exhaust systems of the respective banks by controlling both of opening degrees of the respective EGR valves. One-valve EGR control keeps one EGR valve of the EGR valves in an always closed state, and controls an opening degree of the other EGR valve in that state.
[Patent Literature 1]
Japanese Patent Laid-Open No. 2007-247612
[Patent Literature 2]
Japanese Patent Laid-Open No. 2008-75505